1. Field of the Invention
The invention relates to display systems, and in particular to bi-stable display systems and driving methods thereof.
2. Description of the Related Art
Liquid crystal display (LCD) devices have many advantages such as a small size, light weight and low power consumption, and are applicable in a variety of electronic and communication devices including notebook computers, personal digital assistants (PDA), mobile phones and the like due to its light weight, thin profile, and portability.
Conventional reflective memorable color liquid crystal display devices are widely applicable in electronic books, electronic papers, and the likes. When operating, the conventional bi-stable display devices, such as a cholesteric liquid crystal display device, a driving voltage is applied only when renewal of display data is needed. After driving voltage is applied, arrangements of the liquid crystal are changed, thereby generating different spectrum scatterings to achieve display of color images. Particularly, after the display frame is renewed, the display data can be held steady. Since, the sustained voltage can be released, no power consumption is needed to hold the display data in the display frame, thus applicable display devices are known as bi-stable display devices.
Driving characteristics of bi-stable display devices display non-dynamic image data. Specifically, only when renewal of display frames is needed, then electrical potential is applied to the display devices. However, when considering application in flexible, roll, large-scale display devices, display mechanism requirements are different from conventional display related arts.
FIG. 1 is a schematic view illustrating a structure of a conventional bi-stable display device. Referring to FIG. 1, a conventional bi-stable display device includes a plurality of longitudinal electrodes 17 and a plurality of transverse electrodes 12, respectively extending to peripheral regions 11′, 16′ of the upper substrate 11 and lower substrate 16 of the display device. The aforementioned electrode structures 12 and 17 extend to terminals on two perpendicular lateral sides of both the upper and lower substrates of the display device. The terminals are respectively scanning electrode pads 18 and data electrode pads 13.
Conventional driving method for bi-stable display devices includes connecting both the abovementioned electrode pads 13 and 18 to fixed driving chips 22 and 24. Image data is then transmitted to each of the electrode pads 13 and 18 through the driving chips, thereby renewing display data and frames.
U.S. Pat. No. 7,167,167, the entirety of which is hereby incorporated by reference, discloses a data input system for electronic price tags. Predetermined electrode pads are formed on the peripheral regions of a bi-stable display device. Corresponding electrode pads are also formed on another data input device. When the bi-stable display device and the data input device are in contact, the renewal of a display frame on the bi-stable display device can be completed. When combined, the bi-stable display device is designed to mechanically fix to and contact with the data input device. After renewal is completed, the bi-stable display device is detached from the data input device. The bi-stable display device is a circuit free display device.
U.S. Pub. No. 2006/0170981, the entirety of which is hereby incorporated by reference, discloses a driving method for renewing images of the bi-stable display devices using a roller. The driving method includes applying voltage on a bi-stable display device using a roller with a conductive electrode thereon. When the roller contacts the electrodes on the bi-stable display devices, image data is transmitted to the bi-stable display device to renew a display frame thereon.
U.S. Pat. No. 7,360,688, the entirety of which is hereby incorporated by reference, discloses a mechanism for inputting data in credit cards with a display. An input/output interface for a scrip machine is formed on a lateral side of the credit cards. A point-to-point contact method is used to renew a display frame, and a serial input method is used to transmit the renewed data. The bi-stable display device includes a processor and a memory unit.
Moreover, U.S. Pub. No. 2006/0097957, the entirety of which is hereby incorporated by reference, discloses a display system which includes a combination of several sub-display panels. Each sub-display panel includes electrode contacts, wherein the electrodes of substrates are extended to the same lateral side of the sub-display panel devices in the layout design. After each sub-display panel is arranged and formed into a large scale display device system, image data are controlled by a central control unit and respectively transmitted to each sub-display panel.